RebekahsZ Posted December 1, 2013 Share Posted December 1, 2013 I need to know what size drill bit to use for an ARP wheel stud with an advertised knurl of 0.565". Will be pressing into a 1.25" thick billet aluminum spacer. Quote Link to comment Share on other sites More sharing options...
Xnke Posted December 1, 2013 Share Posted December 1, 2013 How many splines on the knurl? I would drill 17/32. Quote Link to comment Share on other sites More sharing options...
beermanpete Posted December 1, 2013 Share Posted December 1, 2013 0.007" to 0.009" interfernce has worked well for me. ARP is very helpfull, ask them for a recommendation. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted December 2, 2013 Author Share Posted December 2, 2013 Ok guys. Beermans spec is correct according to ARP tech support. But guess what-there ain't no drill bits available from .556-.558! Talked to ARP on this and they say that engineers do stupid stuff like that all the time. Back to the drawing board. There is a .507 knurl stud available for miata at 2.75" instead of 3" length-that would allow for a .500 drill bit. Will measure everything out and see if I could use those. It's only money!!! Quote Link to comment Share on other sites More sharing options...
beermanpete Posted December 3, 2013 Share Posted December 3, 2013 McMaster-Carr sells 0.555" and 0.558" reamers for $44 each. You could buy a reamer to size the hole (drill with 35/64" first). Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted December 3, 2013 Author Share Posted December 3, 2013 I will look into it. Now we are pretty much even money with buying smaller studs. I need to measure and see how big the existing holes are. Thanks for the good info. Have never used a reamer-have no idea how it differs from a drill but I will research it. Thanks! Quote Link to comment Share on other sites More sharing options...
stock600 Posted December 3, 2013 Share Posted December 3, 2013 (edited) Why not drill it to .454 and tap it .500 x 20. I just did mine this week and turned out perfect. Much better IMO also, lock tight the last 1/2" or so and snug them up. Be good for ever that way Tucker Edited December 3, 2013 by stock600 Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted December 3, 2013 Author Share Posted December 3, 2013 Good idea, but the existing holes in the adapters are .522 - larger than a 1/2 bit. That's been the pickle all along. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted December 3, 2013 Author Share Posted December 3, 2013 Obviously I'm not a machinist-I'm sort of a hack. Quote Link to comment Share on other sites More sharing options...
stock600 Posted December 5, 2013 Share Posted December 5, 2013 I hear ya, na just move over and shoot the other 4 through the hub and rotor, then just tap the hub. The hole I started with measured around .480 and it still took the 1/2" tap very well, nice clean threads. They may not be as deep as the other 4 poss. but to the eye they looked as good and torqued down nice. Their 72* apart from each other Quote Link to comment Share on other sites More sharing options...
JMortensen Posted December 5, 2013 Share Posted December 5, 2013 The Miata studs might be the same as the RX7 and Camaro studs. ARP stock number is here if you look. 12mm x 1.5, they fit right into the hubs, no hassles whatsoever. I can't imagine the last .25" being a deal breaker. If they are it's probably time to start looking at different wheels. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted December 5, 2013 Author Share Posted December 5, 2013 Thanks Jon. These studs won't be going into the Datsun hubs-they go into some billet spacer/adapters I bought to allow me to use 15" drag wheels over the AZC big brake kit. I'm forced into a larger knurl by the large diameter but short studs that came in the spacers. I'm now waiting on the drill bit and reamer that beermanpete recommended. Ordered day before yest at McMaster Carr. Thanks!! Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted December 22, 2013 Author Share Posted December 22, 2013 (edited) Job is finished. I used extended ARP studs for an EVO and the reamer that was recommended. I started by using the recommended drill bit, but the hole I was expanding was close enough to what I needed, that I actually got cleaner holes just by using the reamer and skipping the re-drilling. Pressed in the studs using my press. Turned out pretty well. Only potential issue I see is durability. Comparing the short studs that came in the spacers to the ARPs that I replaced with: The original studs have longer, more coarse knurls than the ARPs. Perhaps there is a special spec for the knurls planned to be pressed into aluminum vs those planned to be pressed into steel? Anyway, the job is done. Interestingly, with the longer studs that I put in my billet stub axle flanges, it is possible for me to use all 8 studs when mounting the dual-pattern draglites. So, I ordered extra lug nuts and will be using all 8 studs on each side to secure the wheels. Draglites have a problem with loosing up and I have to re-torque several times during a race day. One of the used draglites I just bought appears to have loosened on the previous owner and banged around on the mounting flange some. Retorque-ing regularly is part of the racing game. Edited December 22, 2013 by RebekahsZ Quote Link to comment Share on other sites More sharing options...
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